Tire pressure indicator



y 1951 w. J. FLANERY ET AL 2,550,986

TIRE PRESSURE INDICATOR Filed Jan. 25, 1949 INVENTOR. Zfl u. 70226 2 Z arra/aHf77a/2prZ ATTD RN EYS Patented May 1, 1951 TIRE PRESSURE INDICATOR Warren J. Flanery and Warren H. Fla-nery, Farmers, Ky.

Application January 25, 1949, Serial No. 72,622

1 Claim. 1

This invention relates to pressure responsive devices for providing signals and particularly warning signals at remote points, and in particular includes a plug threaded in the felly of a pneumatic tired Wheel wherein reduced pressure in or deflation of the tire closes a contact through a diaphragm with a snap movement to light a light or actuate a signal when the pressure in the tire is reduced to a predetermined amount or the tire is deflated.

The purpose of this invention is to provide an improved pressure responsive contact device wherein a contact is made by a snap movement in order to reduce or substantially eliminate the possibility of sparking.

The contact plug of this invention is an improvement over the tire pressure indicator of my co-pending application filed May '7, 1948, with a Serial Number 25,636, now Patent Number 2,502,515, April 4, 1950, in that the contact is made by a diaphragm which operates with a snap movement when air in the tire is reduced to a predetermined pressure.

When pressure responsive devices of this type are actuated by pressure in a tire having a slow leak a movable contact approaches a stationary contact with a slow movement which may cause a continuous spark and the spark burns the contact away. With this thought in mind the in vention contemplates a contact plug having an actuated element therein that moves with a slow movement until it reaches a predetermined point and then actuates a contact element with a snap movement whereby the contact points are closed instantly.

The object of this invention is therefore to construct a contact plug of the pressure responsive type wherein the contacting element actuates with a snap movement.

Another object of the invention is to provide a pressure responsive plug having snap actuated contact therein that may be inserted in the folly of a wheel for a pneumatic tire.

A further object of the invention is to provide a pressure responsive plug that operates with a snap movement which is of a comparatively simple and inexpensive construction.

With these and other objects and advantages in view the invention consists of a new and useful combination, construction, and arrangement of parts as hereinafter more fully described, set forth in the claim appended hereto and disclosed in the accompanying drawings forming a part hereof wherein Fig. 1 is a cross section through a motor vehicle wheel having a pneumatic tire thereon showing a pressure responsive plug in the folly of the rim of the wheel and showing, diagrammatically, a wirin diagram.

Fig. 2 is an end elevational view of the plug looking toward the inner end thereof.

Fig. 3 is a vertical section through the plug illustrating the positions of the elements with the pressure in a tire relieved wherein the contacts are in engagement.

Fig. 4 is a similar view illustrating the positions of the elements with pressure in a tire and with the contacts disengaged.

Referring now to the drawings wherein like reference characters denote corresponding parts. The improved pressure responsive contact plug of this invention includes a plug body In, an inner cylinder l i, which actuates a diaphragm l2, a bushing 13 having an adjusting nut l4 therein, a resilient contact disc 15, and a spring I 6.

The plug body H] is formed with an inner bore I! in which the cylinder I i is slidably mounted and around the bore is a threaded shank [8 with a counterbore IS in the inner end in which a washer 20 and a disc 15 are positioned. The washer and disc are secured in the counterbore by peaning over the inner edge of the shank to form a lip 2 I.

The opposite end of the plug body is enlarged to form a nut 22 which is provided with internal phragm I2 is positioned.

The diaphragm is provided with a centrally disposed opening and the inner edge thereof is positioned in a groove 2'! in the cylinder II, the diaphragm being secured in position by peaning over the inner end of the cylinder to provide a small flange 28.

The bushing 43 is provided with a centrally disposed threaded bore 29 in which the screw it is threaded and the inner end of the screw is provided with a stem 30 over which the spring 16 is positioned, the opposite end of the spring extended into an opening 3| in the cylinder l I.

The bushing i3 is also provided with an insulating sleeve 32 in which a contact screw 33 is threaded and the screw 33 is provided with a lock nut 3G for holding the end of a wire 35. The

' inner end of the screw extends beyond the inner is provided with an annular rib 36 which is PO51" tioned to provide a fulcrum for the diaphragm, as illustrated in Fig. 4 wherein with pressure in the tire the cylinder H is forced toward the diaphragm holding the diaphragm on the fulcrum with the outer edge in contact with the surface of the counter-bore 26 also as shown in Fig. 4. As pressure of air in the tire is reduced the cylinder H moves outwardly and when it reaches a predetermined point the inherent spring of the diaphragm l2 snaps the diaphragm from the position shown in Fig. 4 to that shown in Fig. 3 wherein the diaphragm contacts the inner end of the screw 33 thereby providing a snap movement of the contact elements.

With the parts arranged in this manner the wire 35 may be connected to a plug 3! in an insulating bushing 38 and the plug may be connected to a contact ring 38 on the hub 99 of the wheel. The ring 39 is positioned to engage a contact 4| which may be connected by a wire 4?. to a light 93 and the opposite terminal of the light may be grounded through a wire 99 and a battery 45. The plug body 19 is grounded through the felly and rim of the wheel.

The pressure responsive elements of the plug are readily adjusted whereby contact may be made at any desired pressure. Tension on the spring I6 is adjusted by the screw 1 and the snap movement of the diaphragm is controlled by adjusting the position of the bushing 13.

The parts may therefor be adjusted to instantly light a light or give a signal when air in the tire of a pneumatic wheel is reduced to a predetermined pressure.

It will be understood that modifications may be made in the design and arrangement of the parts without departing from the spirit of the invention.

What is claimed is:

In a pneumatic tire pressure indicating switch, the combination which comprises a plug body having an enlarged end with flat sides and having a threaded shank with a bore extended therethrough and having enlarged annula recesses in the ends of the bore, a cylinder slidably mounted in the bore of the said plug body having a spring retaining socket therein and having an annular flange on the outer end with an annular groove between the flange and end thereof, a tire contact disc positioned in the enlarged recess in the inner end of the said threaded shank of the plug body and positioned to engage the end of the cylinder, a bushing having a threaded bore therethrough threaded in the enlarged recess in the end of the plug body having the enlarged end with flat sides thereon, said bushing having a bore therethrough aligned with the spring retaining socket oi the cylinder and having an annular rib on the inner end positioned around the bore, an adjusting nut threaded in the said bushing, a spring in the plug body with one end in the socket of the cylinder and the other seated against the inner end of the said adjusting nut, a threaded sleeve of insulating material extended through the said bushing and positioned in one side thereof, a contact screw threaded in said insulating sleeve and extended from the inner end of the said bushing, and a circular diaphragm with an opening therein positioned with the inner edge in the annular groove in the end of th cylinder and with the outer part thereof in the enlarged recess in the outer end of the plug body and with the intermediate part thereof riding on the said annular rib on the inner end of the bushing whereby the diaphragm. is spaced from the inner end of the contact screw when the cylinde is forced outwardly by pressure in the tire and the diaphragm is actuated by the spring through the cylinder to contact the said contact serewwhen the pressure is relieved.

NAPJREN J. FLANERY. WARREN H. FLANERY.

REFERENCES CKTED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,183, i86 Pardue May 16, 1916 1,736,534 Jensen et a1. Nov. 19, 1929 1,997,869 Ha ey 9, 1933 1,939,286 Spencer Dec. 12, 1933 2 205,158 Guthrie June 18, 1940 2,257,961 Jones et al. Oct. 7, 1941 2,283,534 Bundy Jr. et al. May 19, 1942 

